Discussions regarding the strength of social ties relate to social capital theory. As Robert Putnam describes it, social capital theory suggests that social networks have value at the micro (individual), meso (community), and macro (societal) levels. An individual's social network is comprised of multiple, multiplex social ties of varying strengths. Strong ties exist among individuals connected within densely knit, homogenous networks such as those involving kin and close friends. Weak ties exist among individuals connected within sparse, heterogeneous networks such as those involving acquaintances.